The Flare-Up Problem

A flare-up — a temporary worsening of symptoms following a therapeutic activity — is among the most demoralising experiences in rehabilitation. It undermines confidence in exercise, reinforces avoidance behaviour, and can reverse weeks of progress in pain desensitisation. Yet flare-ups are virtually inevitable in any rehabilitation programme that is progressive enough to drive tissue adaptation — there is an inherent tension between loading enough for adaptation and loading beyond the current capacity. The clinical skill is minimising flare-up frequency and severity through intelligent progression, and managing the flare-up effectively when it occurs so that it becomes a calibration event rather than a catastrophic regression.

Principles of Safe Progression

Change only one variable at a time. When advancing exercise, change either load, volume, range, speed, or complexity — never more than one simultaneously. If pain increases after a session where both load and repetitions were increased, it is impossible to know which change drove the response. Single-variable progression allows the cause of any flare-up to be identified and corrected.

Use small increments. A 10% increase in weekly loading volume is the standard recommendation in sports science; in rehabilitation populations with sensitised systems or compromised tissue integrity, 5% increments may be more appropriate. Small increments extend the total rehabilitation timeline marginally but dramatically reduce flare-up frequency.

Build a pain buffer before progressing. If the current exercise level is producing 2–3/10 pain, do not progress until it produces 0–1/10 pain consistently across three consecutive sessions. The reduction in pain at a given load reflects adaptation — tissue capacity has grown to accommodate that load comfortably. Progressing before this buffer is established means progressing into territory where the tissue has no adaptive reserve.

Respect the 24-hour rule. Any activity that produces symptoms that persist beyond 24 hours exceeded the tissue's current capacity. Reduce the load by 20–30% at the next session and rebuild more gradually.

Managing the flare-up when it occurs: A flare-up is not a re-injury — it is a signal that the previous load exceeded current capacity. The appropriate response is: (1) relative rest for 24–48 hours (not complete rest — gentle activity speeds recovery), (2) reduce the provoking exercise load by 20–30% at the next session, (3) continue the rehabilitation programme at the reduced load, (4) rebuild progressively once symptoms have settled. Stopping all exercise after a flare-up reinforces the message that exercise is dangerous — it is not. The exercise was simply too much, too soon.

References & Further Reading

  1. Vlaeyen JW, Linton SJ. Fear-avoidance and its consequences in chronic musculoskeletal pain. Pain. 2000;85(3):317–332.
  2. Cook JL, Purdam CR. Is tendon pathology a continuum? Br J Sports Med. 2009;43(6):409–416.
  3. Gabbett TJ. The training-injury prevention paradox. Br J Sports Med. 2016;50(5):273–280.